Vaultwarden is what I use: https://github.com/dani-garcia/vaultwarden/
Their wiki is pretty good assuming you're comfortable with Docker.
Back before I self-hosted, KeePassXC for desktop and Keepass2Android for mobile (along with Synching to sync the database) got the job done.
You could try GymRoutines: https://codeberg.org/noahjutz/GymRoutines
Cloudflare if they have the TLD you want/need (their pricing has no markup). There's also Namecheap and Porkbun. Sometimes they have sales that can make it cheaper.
Is this with your own code or someone else's? It's always harder to understand someone else's code (at least at first). Everyone thinks and writes in a different way.
In either case, I think you could benefit from stepping through the code in a debugger. Depending on what the code is, give some data as input where you know/can guess what the output is. Using the debugger, step through each line to see what happens to the data. It can help break down long or complicated functions into simpler chunks.
Recognition of functions or snippets of code will come through repetition and exposure. Writing code helps more than reading as well. Even with all of that, it's still okay and common to have to look things up or review. I constantly have to check the syntax of C++ library functions, like snprintf, which I have used but not enough to memorize (and that's okay). Don't be discouraged. I've been in my career for 11 years now, around 9 of which is working with embedded C++, and I still feel like an imposter.
The Bolt EUV is the only reason we have an electric car now (personally, I would have gotten the smaller and cheaper Bolt but it was a family decision to go with the EUV). It was reasonable for what you get. The only downside is the slower charging compared to other EVs but I don't plan on taking it for longer trips. We have an ICE for that.
I host for my family which has a mix of Android and iPhone. So far, no complaints about Bitwarden on iOS. Hopefully it works out for you. If self hosting becomes a problem, I think premium is only $10/year and family is up to 6 people at $40/year.
Belter slingshot racers know this all too well. NOTE: Spoiler for an episode in the Expanse which everyone should watch if they haven't already.
I have the same setup with Firefox and Bitwarden without issue. Do you happen to have Firefox setup for restricted battery usage? Android can be quite aggressive with that.